EFun / RMartin / EVD / ...

I noticed, and have read on here about situations where the EVD seems to have less power than normal. I have experienced this myself, and found, as posted, that turning the EVD off and back on resets it to full power.

Is there a known way to get the EVD in this mode. I would like to be able to set it to a lower power setting or "economy" as it might be called on the XM bikes, so that a beginner can try out the EVD for a ride.

Has anyone found a way to consistently get the EVD in this low power mode?

Also has anyone tried replacing the throttle or tweaking anything to get more control when engaging the throttle. It seems to only work in one area on my throttle and is more or less on/off with little variance of power.

Thanks,

Whome

Howdy,

On saturday I ran a real world max range test. With fully charged batteries (pack was at 76V) a second rider and the lights on I wanted to do 40 miles (37 is the most I will need from a full charge.) The bike was fine and the low voltage light didnt even blink under full acceleration. (This is the 21 60AH lfp model.) Voltage on the pack was 69V. I decided to keep going until the light blinked under full accel. About 7 miles more and the light started blinking. So I went home (about 1/2 a mile.) I checked the voltage again and it was at 67.8V. My question then is. No light on accel = 69 V / 21 average (i know thats not the best way but I dont have test leads on the batts yet) = 3.28; light on under full accel = 67.8 v /21 = 3.22V.
Nominal voltage on lifepo is 3.2. So, since both of these readings are above 3.2 did I still have significant stored energy to continue and should I worry about the light under full acceleration? I want to get a feel for range and when to quit with about 30% life left (to keep it out of the danger zone for lower cells and to have 3000 cycles if needed.) Once I get my test leads on I will be able to tell how balanced the cells are. I can say the top 6 are all within .1V of each other but I cant easily get to the bottom 15. Oh and anyone not using their thundersky charger and want to sell it?
thanks
dex

Howdy,

I ordered a 60ah lfp EVD from rmartin last week (7/9/09) and am awaiting delivery. I have a few questions for those that have one. I want to verify that the batts are balanced but given the multitude of ways/opinions on the subject, I am not sure which way to go. Until the warranty is over I have to use the thundersky charger so my automatic options are limited. So, if someone has any advice on how to do it while keeping the warranty intact. I am assuming a few things here.

1. Batteries that start off balanced will slowly drift apart.
2. The further the drift, the faster they will spread.
3. It is possible to manually balance a battery pack given one has access to all the batts.

Here is my understanding of the problem. My battery pack has 21 batteries. Due to the varying AH capacities/internal battery quality they will not all charge/discharge at exactly the same rate. For instance I may have a battery in the pack that is 62AH and one that is 58AH or one that seems more stubborn to take a charge and is always undercharged. Ok let’s look at the stubborn one as an example. Let’s say for argument it’s just this one battery that is a problem in the whole pack. It is always charged less than the others because it won’t charge as fast. So while the others start out at 3.6V the "bad" one is at 3.3V. While that is in the "safe zone" for these batts (2.5V-4.2V) it is possible that it would drop below 2.5 while the rest of the pack are safe at 2.7 because it started out lower. This problem would never "fix" itself since the next charge would bring it up to 3.3 again and not 3.6. The reverse may also be true. I may have a bat that always is high compared to the others so one bat may go higher than 4.2 while the others are at 3.9 at the end of charge (to settle down around 3.6.) Again this wouldn’t be fixed with a new charge since its higher than the others when one started charging it.

Ok now I have a few questions.
1. Wouldn’t over time the high battery "charge" the rest of the batts in the pack and they would self balance (or vice versa the low batt gets a charge from the rest in the pack.) Sort of like water seeking the lowest point. Now, this doesn’t appear to happen given what I have read. I am not an electrical engineer so I am missing some of the basics on the subject. Just for my edification can someone explain why they don’t self balance (a Google search doesn’t really help all that turns up is balancing charges/bms systems.)

2. It seems to me this isn’t really any sort of magical problem that is difficult to solve manually. If there is a batt with too much charge on it, drain the charge off the battery until it is close enough to the other batts in the cell (say all have a .1V spread.) Then check it every month (or more often if one finds monthly isn’t frequent enough and rinse and repeat.) Or if there’s a stubborn cell get a 4.2V charger for lfp batts and charge it on its own until it’s close to the others. (I realize there may be low and high batts in the pack so both methods may need to be practiced on certain cells.) Am I being overly optimistic in thinking I can manually balance the batteries with these methods and they will stay close for the month? I.e. is it too much of a balancing act (pun) for a person to attempt oneself or too time consuming to be worthwhile?

I don’t have the scoot yet so I can’t tell how (un)lucky I am with the pack yet perhaps it won’t be much of a problem. I would also if someone has a bit of time like some guidance in what range I should be shooting for. I’ve read the specs on the batts and they say 2.5-4.2 but I would like to know what people are comfortable with in terms of swing between the low and high batt in the pack. I am assuming take readings fully charged and then depleted after my longest ride so I can determine if they are all in the safe zone and how far they drifted to then get safe max distance traveled.

Also, I would like some guidance with a single 4.2V lfp charger so I can address the stubborn ones if needed (or a bank charger if it turns out I have several low ones.) And also what would be a good safe method for draining off excess charge from the high ones (i.e. hook a light bulb up to it for a while etc.)

Once the warranty is up, I am thinking of going the bank charger way so each cell is charged on its own. Can anyone suggest a solution that can handle 21 cells. My thought is to get the batts close to full with the thundersky charger and then finish them off with something else that charges each cell on its own. But there may be better ways.
Thanks to everyone in advance for any help you could provide.
dex

I just purchased one of these RMartin EVT VRLA's online. It should ship out tommorow. I am hungry for info on it now though while I wait for it to arrive. There seems to be very little online.

Does it have regen?

Any mods done to increase torque or speed?

Any problems?

If you have any info or advice, or a link to another forum that has more EVT owners, I thank you in advance.

Whome

http://cgi.ebay.com/ebaymotors/R-Martin-Electric-Scooter-Moped-50-MPH-NO-GAS-NO-OIL_W0QQcmdZViewItemQQcategoryZ6722QQihZ020QQite...

I need it like a hole in the head, but would grab this if I were local in Arkansas.

Any forum member live nearby that can grab a deal on this one? I wish I won one like the seller did.

I'm trying to find 12V wire to tap into that is switched by the ignition. That is, when the key is turned to the ON position the wire has 12V. And when the key is OFF the wire has 0V. My hope is that there is one under the seat.

I don't think any of the wires going to the taillight/brakelight/turnsignals fit the bill. But I see other wire harnesses accessible under the seat. Maybe one of them has what I want?

Here's two pictures of them (I see 3 harnesses here) taken from the rear of the EVD. Second picture is a close-up. Is there a wire in this group that I can use for 12V?

Thanks!
Jerome

Seems like the poor EVD gets little attention on this forum. I have not posted much because it has been a great scooter with very little problems. It does what it was suppose to and I have been pretty happy with it. R Martin is quick to respond and has taken care of all of my part requirements in a timely manner.

The process of insuring and registering the scooter with the Nevada DMV was very easy. The insuring took a little work to educate them with pictures.

When I first got my EVD I had one of the 60AH Lithium cells that was a little stubborn taking a full charge. After I cycled the individual cell a couple of times it has kept pace with the other cells. The 60 AH cells are more robust than the 40 AH cells and do not have the voltage drops under load that you see in the 40 AH cells.

For those that have been having tire balance issues, a product Dynabeads is available that can be run in tube or tubeless tires that have done wonders in my other motorcycles http://www.innovativebalancing.com/motorcycle.htm . It can however be a challenge feeding the ceramic beads thru the valve stem.

Like MikeB I had been experiencing the low voltage warning in the cold weather (below 45F). But it never caused an issue with the scooter.

I added two additional cells to the pack and currently have been running a 23cell 60AH pack. It will go faster than I feel comfortable going in a scooter +65mph(GPS).

It would be interesting to find out what if any real difference there is between the EVD and the XM-500Li. To me they look like the same thing with the XM being more exspensive, but I may be wrong. After my early XM3500 experiences I doubt I would buy another X-treme.

Gordon

Well I got the EVD about a week and a half ago and I have to say I am quite impressed, the shipping crate was somewhat difficult to remove, and we were doing it under the cardboard box in the rain... But does it move, the main units are MPH unlike the XM series and it seems to have the same realistic top speed as the 3500li. I still need to test the speedometer against a car before a cop decides to test me, but I just try and keep up with traffic and it works fine. I think I will notice the difference in battery life come summer because its been about 40F here constant and its either somewhat covered outside at work or in my garage which gets kinda cold anyway. I have not mapped out the range so far, my 16 mile round trip at 40mph most of the way, up to 50-55 for a mile or two pulls me to about half charge when I am giving it decent throttle uphill, so say 30 miles is pretty reasonable at that speed in the rain and wind at about 40F. I believe the ratio is something like every 15 degrees drops the lead acid capacity by 25%? I may have it backwards or something like that but I think them saying 50 mile range is believable.

On a very slight downhill I pull 55 pretty easily (speed limit is 45) and on the way back I can manage 50 but it takes me a bit, sometimes cars get kinda annoyed but lets see them do it in one gear. I am also tucking a decent amount when riding it which helps greatly, in the rain when tucking the windshield does its job and I do not get rain on my helmet. Feels stable at the higher speeds although I am getting used to it still and am sure it will get even better. One thing I have noticed is occasional controller lag, could be how I am riding it but there seems to be a throttle delay sometimes.

I have noticed a few things as to build quality, overall very solid, front fairing seems a little janky but I can live with it. Brakes feel like I can stop pretty well although I need to loosen them a bit because of rubbing. Front wheel developed a squeak about 2 or 3 days in and some Tri-Flow fixed that right up. The side shield for the brake and the swing arm had one bolt in the back of the two holes welded improperly so the screw would not go in more than half an inch and I stripped it out a bit as is, I got a decently sized zip tie that fit right in there and it matches the black so its mostly invisible and does the job, I keep an extra on me just in case it breaks. There is a small gap in just one or two places I have noticed that the plastic does not fit properly together and I can't tell why but its only noticeable if you are riding it and look straight down (not advisable unless stopped). My seat pops up pretty quick and has actually nailed me in the face on two separate occasions, the first time opening was one of them. I still love the seat however, there is a hole at the base near the spring and right now I have a 35 foot outdoor extension cord coiled up in there that I can just leave attached to the charger and it takes up almost no otherwise usable space, there is batteries and stuff down there so it coils up and pulls out but never goes anywhere as far as I can tell. Charging at work with that extension cord is fairly painless, there is enough of a gap in the seat to allow for plenty of airflow and if you live and work downtown it might be hard to charge but you would probably only need to every couple to few days.

I have the VRLA (Lead acid) version that is cheaper than the lithium and I can not even imagine the performance difference between the two. To go lithium would be 1500 more and I figure in two years when these need replacing I will get me some capacitors fitted instead. Or just buy an electric car.... Anyway I highly recommend this scooter to pretty much anyone, registration has been somewhat difficult surprisingly but I am fairly sure it will work out just fine.

Ask if you have questions.

So my EVD arrived yesterday. Got the VRLA one. Unpacked it and put it together.

Only problem I have is the front right turn signal light does not work. When I turn it on I get a fast beeping. The rear right signal flashes. The left front and rear work fine and do a normal beeping.

So how do I troubleshoot what is wrong with the front right signal? How do I disassemble?

I'll call Randall on monday to ask him, but thought I'd check here too.

Another minor problem is the storage compartment. When I unlock it often it does not open. When that happens I have to pull hard on the seat to open it.

I rode it in 27 degree temp today it and did just fine.

Enjoy the weekend.

Well, now that there's a dedicated subforum to pollute...

I spent my afternoon at the DMV. To complete the registration, I needed to have the vehicle inspected. The vin is on the outside of the battery case on the right side and on the left side of the frame underneath the seat, removed with four phillips screws. The engine number is six digits on the rear left wheel that might be hidden between say 8 o'clock and 12 o'clock.

That the vehicle is pure-electric caused a moment of confusion when the guy started talking about an emission sticker, thinking it was hybrid but with that clarified everything was okay.

Insurance from the motorcycle people affiliated with esurance was great. I guess just this summer they received training and a special binder for electric two-wheel vehicles. They had efun listed so I had no problem with them accepting my scooter.

The scooter did everything I need it to going up the Big Hill from the coast to inland and the ride back down to just above sea level was so fast I wish my iPhone had GPS. It also kept up with the rush hour traffic in front of me on a perfectly flat stretch just outside of Seaworld that's signed at 50 and runs at 55-65 generally.